Microstructures and mechanical properties of Ti₃SiC₂/TiC-Al₂O₃ composites synthesized by reactive hot pressing

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• 作者：Yanzhi Cai ; ^{yzcuxb@yahoo.com.cn} ; Hongfeng Yin ; Liqing Pan ; Panjun Chen ; Gaolei Sun
• 关键词：Mechanical properties ; Ti3SiC2/TiC&ndash ; Al2O3 composites ; In-situ reaction ; Microstructures
• 刊名：Materials Science and Engineering: A
• 出版年：2013
• 出版时间：1 June, 2013
• 年：2013
• 卷：571
• 期：Complete
• 页码：137-143
• 全文大小：1924 K

文摘

Ti₃SiC₂/TiC-Al₂O₃ composites with different Al₂O₃ contents were fabricated by in-situ reaction and hot pressing sintering. Laminar Ti₃SiC₂ grains and granular Al₂O₃ grains were densely packed and tightly bonded, and cubic TiC grains presented in the surfaces of Ti₃SiC₂ grains. Al₂O₃ significantly restrained the grain growth of Ti₃SiC₂ matrix. The dispersed Al₂O₃ grains inclined to be pulled out, but Al₂O₃ aggregates inclined to be cut by the crack front at the crack surface. The flexural strength and fracture toughness first increased and then decreased with the increasing Al₂O₃ content. The composite with 20 wt % Al₂O₃ addition showed the highest flexural strength of 649 MPa and with 10 wt % Al₂O₃ addition showed the best fracture toughness of 7.15 MPa m^1/2. The mechanism responsible for improved mechanical properties for Ti₃SiC₂/TiC-Al₂O₃ composites were the synergistic action of particulate dispersion reinforcement, fine-grain toughening, grain pullout, microcrack deflection, and lamella bending and slipping from three different kinds of grains.